Originally Posted by zraffz (Post 859864)

I'm a little up in the air about running a cast crank although I don't think I'd have any issues. One question, how can a crank be good for a 5.7" rod or 6" rod like this one is claiming?
http://www.summitracing.com/parts/sca-935050l

Originally Posted by zraffz (Post 859871)

Most cranks are advertised as a specific length rod. No idea why but I always figured it had something to do with it. I understand why the pistons would need to be set for a specific length rod.
Thanks for clearing that up guys.

Originally Posted by LTb1ow (Post 859890)

Just to be philosophical... why run a cast crank with forged $600 compstar rods..?

Originally Posted by sweetbmxrider (Post 859908)

He's saying you are using good budget rods on a **** crank.

Originally Posted by LTb1ow (Post 859913)

Yarly.

No sense in have 700hp rated rods on a 500hp rated crank.

Originally Posted by zraffz (Post 859926)

Have seen many ten and eleven second cars at the track running cast cranks. Really, even online the only times I've heard of a crank getting destroyed was with forced induction but yet I've seen rods snap in half on higher rpm motors.

Originally Posted by Paul Huryk (Post 859946)

You should be able to push out 500 to 525 engine hp with your motor with that setup of heads and cam.

Originally Posted by zraffz (Post 859958)

You really think so? I was honestly expecting to be around 460-480 crank. Obviously wouldn't complain if I made more though :wink:

Anybody know anything about the company Ohio Crank? They have the crank I need for $495. Maybe a stupid rookie question but what determines if a crank is going to be internally or externally balanced before the balancing process occurs? (I ask because ohio crank doesn't specify and I would prefer an internal/neutral setup like I am familiar with).

You guys make a valid point. I'd rather do it right the first time and be able to trust what I built.


Edit:
And how are these rods? They are balanced, clearanced and weight matched.
http://www.summitracing.com/parts/sc...1qls/overview/

Originally Posted by zraffz (Post 859958)

You really think so? I was honestly expecting to be around 460-480 crank. Obviously wouldn't complain if I made more though :wink:

Anybody know anything about the company Ohio Crank? They have the crank I need for $495. Maybe a stupid rookie question but what determines if a crank is going to be internally or externally balanced before the balancing process occurs? (I ask because ohio crank doesn't specify and I would prefer an internal/neutral setup like I am familiar with).

You guys make a valid point. I'd rather do it right the first time and be able to trust what I built.


Edit:
And how are these rods? They are balanced, clearanced and weight matched.
http://www.summitracing.com/parts/sc...1qls/overview/

Originally Posted by Paul Huryk (Post 859966)

Well, I checked out a 383 that Lingenfelter built and is in his book "JL builds SBC engines" and a similar setup put out 493hp at 6000rpm with a carb. Now your heads flow a little better and your cam is one step up, so I would think that if perfectly tuned it would be over 500hp.

Either you leave what you have (maybe change bearings, bolts, and oil pump) or you build it right with a solid bottom end - no reason to do things half way... And then have to do it again.

Originally Posted by zraffz (Post 860000)

I'd bet on a stripped down engine dyno this combination could do 520 horses with a good tune. I have a tendency to think crank horsepower as fully dressed through mufflers and full accessories like how new cars are rated. I don't doubt this is a 460-480 hp motor with that rating.

Originally Posted by Paul Huryk (Post 860023)

I'll re-read the article tomorrow to see if the accessories were attached. You must be thinking about the 60's and early 70's factory ratings that were without any accessories and fully tuned - production cars rated at 300hp ran more like 225 on the street...

Originally Posted by zraffz (Post 860027)

Exactly what I am thinking. I thought most crate motors were dynoed without accessories and I know most magazine articles publish pictures on the dyno without accessories to boast larger HP gains than what they truely have.

Originally Posted by zraffz (Post 860027)

Exactly what I am thinking. I thought most crate motors were dynoed without accessories and I know most magazine articles publish pictures on the dyno without accessories to boast larger HP gains than what they truely have.

Originally Posted by Paul Huryk (Post 860113)

Doesnt say if there are accessories on the motor:
489hp at 6000
478 TQ at 5000
This motor obviously doesn't require a solid roller since it only revs to 6500, plus the heads are limited to about 260cfm flow - although they are super high velocity ports.

Originally Posted by WildBillyT (Post 860116)

I thought they were. As installed in a vehicle, SAE net.

Originally Posted by zraffz (Post 860203)

My heads might flow right around that and but my cam is a bit more agressive. Guess I'll never know for sure but I'm more interested in what it will run more than anything.




Can't really believe crate motors are rated that way. I've seen quiet a few boasting larger numbers than I could really believe possible with the top end they had. I think companies like GMP rate them SAE net but most don't.

For instance they rate a stock rebuilt LT1 long block at 330HP/350TQ in Summit.

Originally Posted by Damon at NastyZ

GMPP crate motors are rated the same way they do for production line engines. It's SAE NET at the flywheel. However, the CONFIGURATION of the motor as-tested is not necessarily the same as a production line engine.

In a production line engine HP is rated "as installed" with all accessories, full factory exhaust system, factory air box, etc. Since a crate motor will have unknown as-installed configuration, they sorta "pick and choose" the configuration of the engine for the test. In the case of the popular 260HP 350 they chose headers, high flow exhaust, aftermarket dual plane intake, 4bbl carb, low-restriction air cleaner with few front end accessories (just water pump, I think) and, of course, tuning optimized for power.

That's why that engine (a veritable clone of the LM1 in a late 80s Z28) is rated much higher than the factory installed engine was. The factory installed engine had cast iron manifolds, single exhaust, cat converter, factory cast iron intake with a QJet topped by a quiet air cleaner assembly and a bunch of emissions equipment along with a full complement of front end accessories. Tuning was also designed to meet emissions, not necessarily maximize HP. That's a lot of differences.

Please note that "260 HP" crate engine has been rated at 195, 205, 225 and 250HP over the years. The engine has been almost unchanged since the 1980s, however. Only the rating has changed and only becuase GM used different configurations for the testing. More conservative in the past, more liberal in recent times. That "260 HP" engine is the one that GM has most stretched the believability of the rating.

However, almost every other crate motor GM just carries over the production line HP rating to the equivalent crate motor. Which means if you slap some headers on them and a free flowing intake system they often put out considerably more power than their official rating.

LAST DIFFERENCE...... Only the mother ship consistently rates using SAE numbers. Just about everything aftermarket is quoted in STP (Standard Temp and Pressure) numbers. SAE is more "stingy" while STP is more "liberal". You can imagine why the aftermarket would tend to gravitate to the more "liberal" STP numbers- it makes for higher power numbers which is good for business.

Originally Posted by WildBillyT (Post 860229)

Do you have a link? I can't find it.

Regarding crate engines, this dude knows his stuff cold:



All I could find was this at Jeg's:

http://www.jegs.com/i/Blueprint-Engi...5029C/10002/-1